Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Quantos turistas de cada país visitaram destinos sustentáveis?
 ###Tabelas: 
CREATE TABLE Sustainable_Destinations (id INT, destination_name VARCHAR(50), sustainable BOOLEAN); CREATE TABLE Tourists_Destinations (tourist_id INT, destination_id INT, visit_date DATE); INSERT INTO Sustainable_Destinations VALUES (1, 'Eco Village', true); INSERT INTO Sustainable_Destinations VALUES (2, 'Green City', true); INSERT INTO Tourists_Destinations VALUES (1, 1, '2022-01-01'); INSERT INTO Tourists_Destinations VALUES (2, 2, '2022-01-02'); INSERT INTO Tourists_Destinations VALUES (3, 1, '2022-01-03');
SELECT Tourists.nationality, COUNT(DISTINCT Tourists_Destinations.tourist_id) AS num_tourists FROM Tourists_Destinations INNER JOIN Tourists ON Tourists_Destinations.tourist_id = Tourists.id INNER JOIN Sustainable_Destinations ON Tourists_Destinations.destination_id = Sustainable_Destinations.id WHERE Sustainable_Destinations.sustainable = true GROUP BY Tourists.nationality;